Hi.. Thanks for the query.. As per your complain in case if you have Allergic reaction then you can take Loratidine to relieve the symptoms.. You can take it with the antibiotic and decongestant too but only after consulting your Physician as it is a prescription medications.. As your allergy symptoms are recurring I would suggest you to consult an Allergist and get allergic tests like Patch test, RAST test, food challenge test etc can help in diagnosis and treatment can be done accordingly.. The tests will help in ruling out the exact cause of the allergen and once you know the cause of the allergic reaction you can avoid exposure to it to prevent allergy attack.. He can be advised to take anti allergics along with topical application of Calamine or Caladry lotion.. He can also be instilled an Immunotherapy that will help in reducing the severity and frequency of allergic attack.. Once the allergen is ruled out avoiding exposure to it can prevent the allergy symptoms.. Hope this helps.. Regards..